1. Field of the Invention
The present invention relates to apparatus for reducing electrical fault voltages in electrical conductors, the apparatus having at least one excess voltage or surge suppressor, and a holder which accommodates the excess voltage or surge suppressor and which contains an insulating housing and electrical connection means for connection of external electrical conductors to the apparatus.
Apparatus of the above type fulfils the purpose of keeping harmful over-voltages away from, or at least reducing them to a tolerable magnitude for, current consumers with sensitive electrical components, such as in particular semi-conductors, such over-voltages arising for instance in atmospheric storms, in coupling or decoupling reactance-compensating capacitors, in short-circuiting, and in nuclear explosions etc.
2. Description of the Prior Art
Surge suppressors for various operational voltages and discharge current magnitudes have been known for some time. They consist for instance of an electrical discharge path filled with a noble gas and/or a voltage dependent electrical resistance ("Varistor") with a non-linear current/voltage characteristic. Various manufacturers also offer matching holders which accommodate one or more surge suppressors and connection terminals for external electrical conductors. These known holders have differing constructional forms which also require different types of mounting and of connection to an external electrical conductor. In practice, the need often arises to mount apparatus of the above-mentioned type in a switch box together with the usual connecting branch, and earthing terminals. Consequently, this has hitherto been relatively complicated and expensive, because on the one hand the commercially available electric terminals and the known noise or fault voltage protection apparatus of the abovementioned type required different securing means and supporting means so that special constructions for at least one part of these securing and supporting means have been necessary. Regard had also to be had to the fact that to achieve a satisfactory protection against fault voltages, especially voltage surges, no unprotected electric supply lines were allowed to be led in the vicinity of and parallel with the protected conductors, this being a requirement which significantly influences the placing of the terminals and of the fault voltage protection apparatus and appreciably restricts the freedom in choice of mechanical securing and supporting means as regards construction and disposition.
It is therefore an aim of the present invention so to construct apparatus of the above-mentioned type for reducing fault voltages in electrical conductors that it should be simply mountable on the same securing and supporting means as commercially available terminal blocks, while at the same time it should assure better discharge of fault voltages to a protective ground conductor.